Screen printers are configured to print a paste on a substrate by bringing the substrate held by a substrate holder into contact with a mask from underneath the mask and by then moving a printing head such as a squeegee on the mask. Here, contact between the substrate and the mask is performed based on an imaging result (information about the position of the substrate) obtained by imaging the substrate using an imaging device such as a camera. In addition, in order to improve printing accuracy, mask cleaning is also performed to remove the paste adhering to the mask by sliding a mask cleaner on a lower surface of the mask separated from the substrate.
In the screen printers, the imaging of the substrate by the imaging device and the mask cleaning by the mask cleaner are performed as described above. However, since both the imaging device and the mask cleaner are disposed in a region between the substrate holder and the mask, it is difficult to perform the imaging and the cleaning in parallel and it is necessary to perform the imaging and the cleaning serially at different times (see Patent Document 1, for instance).
Patent Document 1 is JP-A-2013-43418.